feat(@schematics/angular): Add pipe schematic

Author: jschwarty

packages/schematics/angular/collection.json

@@ -30,6 +30,11 @@
       "description": "Create an Angular module.",
       "schema": "./module/schema.json"
     },
+    "pipe": {
+      "factory": "./pipe",
+      "description": "Create an Angular pipe.",
+      "schema": "./pipe/schema.json"
+    },
     "service": {
       "factory": "./service",
       "description": "Create an Angular service.",

packages/schematics/angular/pipe/files/__path__/__name@dasherize@if-flat__/__name@dasherize__.pipe.spec.ts

@@ -0,0 +1,8 @@
+import { <%= classify(name) %>Pipe } from './<%= dasherize(name) %>.pipe';
+
+describe('<%= classify(name) %>Pipe', () => {
+  it('create an instance', () => {
+    const pipe = new <%= classify(name) %>Pipe();
+    expect(pipe).toBeTruthy();
+  });
+});

packages/schematics/angular/pipe/files/__path__/__name@dasherize@if-flat__/__name@dasherize__.pipe.ts

@@ -0,0 +1,12 @@
+import { Pipe, PipeTransform } from '@angular/core';
+
+@Pipe({
+  name: '<%= camelize(name) %>'
+})
+export class <%= classify(name) %>Pipe implements PipeTransform {
+
+  transform(value: any, args?: any): any {
+    return null;
+  }
+
+}

packages/schematics/angular/pipe/index.ts

@@ -0,0 +1,91 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+// TODO: replace `options: any` with an actual type generated from the schema.
+// tslint:disable:no-any
+import {addDeclarationToModule} from '../utility/ast-utils';
+import {InsertChange} from '../utility/change';
+
+import {
+  Rule,
+  Tree,
+  apply,
+  branchAndMerge,
+  chain,
+  filter,
+  mergeWith,
+  move,
+  noop,
+  template,
+  url,
+} from '@angular-devkit/schematics';
+import * as stringUtils from '../strings';
+
+import 'rxjs/add/operator/merge';
+import * as ts from 'typescript';
+import {buildRelativePath, findModule} from '../utility/find-module';
+
+
+function addDeclarationToNgModule(options: any): Rule {
+  return (host: Tree) => {
+    if (options.skipImport) {
+      return host;
+    }
+
+    let modulePath;
+    if (options.module) {
+      if (!host.exists(options.module)) {
+        throw new Error(`Module specified (${options.module}) does not exist.`);
+      }
+      modulePath = options.module;
+    } else {
+      modulePath = findModule(host, options.sourceDir + '/' + options.path);
+    }
+
+    const sourceText = host.read(modulePath) !.toString('utf-8');
+    const source = ts.createSourceFile(modulePath, sourceText, ts.ScriptTarget.Latest, true);
+
+    const pipePath = `/${options.sourceDir}/${options.path}/`
+                     + (options.flat ? '' : stringUtils.dasherize(options.name) + '/')
+                     + stringUtils.dasherize(options.name)
+                     + '.pipe';
+    const relativePath = buildRelativePath(modulePath, pipePath);
+    const changes = addDeclarationToModule(source, modulePath,
+                                           stringUtils.classify(`${options.name}Pipe`),
+                                           relativePath);
+    const recorder = host.beginUpdate(modulePath);
+    for (const change of changes) {
+      if (change instanceof InsertChange) {
+        recorder.insertLeft(change.pos, change.toAdd);
+      }
+    }
+    host.commitUpdate(recorder);
+
+    return host;
+  };
+}
+
+export default function (options: any): Rule {
+
+  const templateSource = apply(url('./files'), [
+    options.spec ? noop() : filter(path => !path.endsWith('.spec.ts')),
+    template({
+      ...stringUtils,
+      'if-flat': (s: string) => options.flat ? '' : s,
+      ...options,
+    }),
+    move(options.sourceDir),
+  ]);
+
+  return chain([
+    branchAndMerge(chain([
+      filter(path => path.endsWith('.module.ts') && !path.endsWith('-routing.module.ts')),
+      addDeclarationToNgModule(options),
+      mergeWith(templateSource),
+    ])),
+  ]);
+}

packages/schematics/angular/pipe/schema.json

@@ -0,0 +1,47 @@
+{
+  "$schema": "http://json-schema.org/schema",
+  "id": "SchematicsAngularPipe",
+  "title": "Angular Pipe Options Schema",
+  "type": "object",
+  "properties": {
+    "name": {
+      "type": "string"
+    },
+    "path": {
+      "type": "string",
+      "default": "app"
+    },
+    "sourceDir": {
+      "type": "string",
+      "default": "src"
+    },
+    "flat": {
+      "type": "boolean",
+      "default": false,
+      "description": "Flag to indicate if a dir is created."
+    },
+    "spec": {
+      "type": "boolean",
+      "default": true,
+      "description": "Specifies if a spec file is generated."
+    },
+    "skipImport": {
+      "type": "boolean",
+      "default": false,
+      "description": "Allows for skipping the module import."
+    },
+    "module": {
+      "type": "string",
+      "default": "",
+      "description": "Allows specification of the declaring module."
+    },
+    "export": {
+      "type": "boolean",
+      "default": false,
+      "description": "Specifies if declaring module exports the pipe."
+    }
+  },
+  "required": [
+    "name"
+  ]
+}